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I moved into a new house that already had speaker wire hanging out of the wall in the living room, all set up for a 5.1 surround system.
I've bought some nice speakers: Q acoustics 7000i plus
I've bought a nice av receiver: Denon avr3300x

But now my complete naivety when it comes to setting things up has come to light. Although I have speaker wire hanging out of the wall, with a black and red wire, the other end seems to be an RCA head. (2 wires going into a single RCA plug.) One for L, R, C in blue and an L and R in orange. Which I assume are front left and right, center and surround left and right respectively.

The Denon expects speaker wire connections, not RCA, and I although I can google and find plenty of info about converting speaker wire to RCA, I can't find anything about the other way round, except some warnings about low level and hight level that I didn't really understand, but I get the impression speaker cable and whatever an rca line is, are not the same thing.

So, is it speaker cable? can I just chop the ends off? Do I need an adapter? I know the simple thing would just be to buy a big reel of speaker cable and use that but it's not that easy as the existing cable is already inside the walls and under the flooring so I'd like to be able to use that if possible.

Well-known Member

The cables should work, just cut the RCA connectors off and strip the wire. Are there any markings on them to indicate which is positive (red) and negative (black)? Its crucial you get the right way round as kit can be damaged if not.

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I can try it and see... no visible markings before I cut it off, I'll give it a try tomorrow and check once stripped back. Failing that, I believe I can test it with a battery or some such? I'll google it before I try anything. If all else fails I'll buy some fresh speaker cable and take it round the room, 2.5mm seems to be more than twice the price of 1.5mm is the difference worth it?

Well-known Member

There are some old style all in one systems such as my old Sony 5.1 all in one system and some Logitech systems that use RCA connectors to connect the satellites to the amp console so I think this is what these would have been used for, could be wrong though! If this is the case then just chop the ends off and use as regular speaker cable!

Well-known Member

True, to ensure all speakers are 'in phase' (but the AVR auto setup will detect this problem)

as kit can be damaged if not.

Click to expand...

How can kit be damaged by speaker wire reversal? It's an AC signal. No harm will come from having them reversed (except sonically, if a speaker is phase reversed, but that's simple to find and fix).

OP: As post #13 some all in ones and cheaper end amps use(d) RCA plugs.

The plastic RCA covers will pull off and the wires will have been soldered on by the previous owner ... The wire going to the centre pin will almost certainly be the hot 'red' connection and the other the 'black' (most common convention used). Use some tape or sleeving to mark the wires before you snip them off the plugs (any colour will do to identify which one was the hot 'pin'. It matters not which is finally connected to the amplifier red or black terminals, all you need to ensure is that all 5 ex-RCA wires are marked and connected the same way.

Personally those wires look just about adequate for domestic listening. Only need upgrading if you listen very loud or with inefficient speakers. Suck it and see for now.

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Well I took the plunge and cut the ends off. There was no markings at all to see which was red or black. I tried using a battery to see which way the membrane moved but only had a double aa and if it moved it was too small a movement to see so I had to wire it up at a guess and hope the 3300's microphone would pick up any out of phase ones in it's calibration tests.

Moment of truth, fired up the Denon and... it worked! Every speaker produced sound. Ran the denon audyssey multieq xt32 and it told me to check the centre and right surround speakers for phase. So I swapped them round and ran it again and it reported no problems this time. So hopefully, everything is correct!

Finished the test, fired up a movie and the sound quality is really good. I can only have the sound relatively low because of neighbours. and I'm no audiophile so if I'm suffering because of thin cables I can't hear it.

I'm very happy it's working. Thanks for all the advice, and hope this thread is useful to someone else in the future!

Well-known Member

Great news.
Now is the time to mark the wires with something to identify which one is 'red' and which is 'black'... just in case you need to disconnect and re-connect them in the future. (Decorating, receiver fault/upgrade... etc.,.)

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Yes, I got an amazing sticker pack with the denon that lets me peel off stickers for front left, center etc, which was a really nice touch. I'm going to mark up the cables tonight, so it's clear for the future